The invention is relative to a bobbin winding unit of a textile machine for producing cross-wound bobbins, sometimes referred to as cheeses.
Bobbin winding units in textile machines for producing cross-wound bobbins, or cheeses, are equipped typically with a splicing device for connecting an upper yarn to a lower yarn. Such splicing devices utilize a suction nozzle pivoted by an electromotor drive for manipulating the upper yarn between a position in which the suction-nozzle mouth is disposed in the area of the surface of a take-up bobbin for locating the upper yarn and a position in which the upper yarn is placed into the splicing device. The suction nozzle may also have a sensor device for sensing the presence of the upper yarn.
Such bobbin winding units are known, e.g., from Japanese Published, Unexamined application Hei 5-246,626. This publication describes a winding unit for an automatic bobbin winder which unit comprises a suction nozzle which can pivot in a defined manner via an associated individual drive. A sensor device for detecting a sectioned upper yarn is installed inside the suction nozzle. In addition, the maximal yarn search time, that is, the time during which the suction nozzle remains positioned on the surface of a take-up bobbin being wound, can be adjusted via a time function element. If the free end of the upper yarn to be spliced is not found by the sensor device within the preset search time, the yarn search and therewith the attempt at yarn connection is stopped.
DE 42 31 958 A1 describes a winding unit with a yarn connection device which comprises a pivotably mounted multifunctional yarn manipulating element by which both the upper yarn and the lower yarn can be placed in a splicing device. While the yarn manipulating element is directly taking up the lower yarn, the upper yarn is taken up indirectly via an additional flat nozzle. The yarn manipulating element can dock on this flat nozzle for accepting the upper yarn. The flat nozzle is connected to a motor which pivots the flat nozzle during the winding process in such a manner that the nozzle mouth remains in the area of the surface of the take-up bobbin. It is moreover possible to vary the spacing of the mouth of the flat nozzle to the surface of the take-up bobbin by appropriately regulating this motor.